The present invention relates to adjusting colors in digital images. Conventional image processing programs provide a number of tools that allow users to adjust colors in digital images. Such color adjustment tools typically operate by changing pixel values (which can represent color, transparency or other information associated with the image pixels) throughout the image, or in a selected region of the image. In conventional operations, colors may be adjusted by changing, for example, the color balance of the image, or the chrominance and/or luminance (or the hue, saturation, transparency, and/or brightness) of colors of selected pixels, or by changing the color values themselves according to a predetermined color adjustment algorithm defined for the particular operation. Particular adjustment operations can include, for example, retouching operations such as smudging, blurring, toning, or sponging, as well as the correction of defects resulting from scratches or dust in selected regions of the image. The amount of the adjustment can be determined based only on information associated with the single pixel to be modified, such as when making a general change in hue, saturation, transparency, luminance, color balance, contrast, for example. Alternatively, the change may be determined by analyzing multiple pixels, such as when applying a Gaussian blur, which determines the amount of change by forming a weighted average value of pixels in the vicinity of the pixel to be changed.
Some conventional image processing programs provide tools implementing predefined adjustment algorithms designed to address specific situations or defects commonly found in digital images. One such defect is the redeye effect that can result when the retina of the human eye is exposed to bright light, such as the flash of a camera. This causes portions of the eye, typically portions of the pupil and/or iris, to reflect red light, and therefore appear red in the resulting photographic image. Redeye correction tools typically operate by inspecting individual pixels and/or by applying one or more predefined two-dimensional templates representing various appearances of the human eye to identify a potential redeye site within a user-specified region of the image, and applying a predetermined correction to the identified redeye pixels.